Automatic stop mechanism for arresting manual raising of feed tables



Sept. 20, 1966 G. J. ZAHRADNIK 3,273,334

AUTOMATIC STOP MECHANISM FOR ARRESTING MANUAL RAISING OF FEED TABLES Filed May 27, 1964 5 Sheets-Sheet 1 Sept. 20, 1966 G. J. ZAHRADNIK AUTOMATIC STOP MECHANISM FOR ARRESTING MANUAL RAISING 0F FEED TABLES 5 Sheets-Sheet 2 Filed May 2'7, 1964 Sept. 20, 1966 a. J. ZAHRADNIK 3,273,384

AUTOMATIC STOP MECHANISM FOR ARRESTING MANUAL RAISING 0F FEED TABLES 5 Sheets-Sheet :5

Filed May 27, 1964 Sept. 20, 1966 G. J. ZAHRADNIK AUTOMATIC STOP MECHANISM FOR ARRESTING MANUAL RAISING OF FEED TABLES 5 Sheets-Sheet 4 Filed May 27, 1964 Sept. 20, 1966 e. .1. ZAHRADNIK AUTOMATIC STOP MECHANISM FOR ARRESTING MANUAL RAISING OF FEED TABLES 5 Sheets-Sheet 5 Filed May 2 1964 United States Patent nois Filed May 27, 1964, Ser. No. 370,584 Claims. (Cl. 271-22) This invention relates to duplicators, printing presses or the like and pertains particularly to improvements in sheet feeding mechanisms whereby sheets made of paper or the like are fed into such duplicators.

The invention relates particularly to sheet feeding mechanisms of the type in which a stack of paper sheets is supported on a table which is adapted to be moved upwardly by an automatic mechanism, so that the top of the stack of sheets is maintained at a nearly constant elevation as the sheets are fed, one at a time, from the top of the stack. In the use of a machine of this kind, it is necessary to replenish the stack from time to time by adding a pack of sheets to the top of the stack. When this is done, the usual procedure is to lower the table manually, as far as it will go, to make room for the new sheets, and then to raise the table manually to bring the top of the stack to approximately the correct level for normal opera tion of the sheet feeding mechanism.

One object of the present invention is to provide a new and improved automatic stop mechanism which automatically arrests the raising movement of the feed table when the top of the stack has been raised to the desired level. Such automatic mechanism greatly simplifies and facilitates the manual raising of the feed table in that the operator merely raises the table as far as it will go, as governed by the automatic stop mechanism. The operator does not need to take any particular care to raise the stack of sheets to the correct level.

A further object is to provide a new and improved automatic stop mechanism of the foregoing character, in which the stop mechanism is operated by a corner separator or other member which is engageable by and movable upwardly with the top of the stack.

Another object is to provide such a new and improved automatic stop mechanism in which there is an overriding connection between the feed mechanism and the automatic stop mechanism, so that the automatic stop mechanism is rendered ineffective when the feed mechanism is put into operation. In this way, the automatic stop mechanism does not interfere with the free raising movement of the feed table during the normal operation of the feed mechanism.

A further object is to provide such a new and improved mechanism in which the control member which stants the feed mechanism is linked to the automatic sto-p mechanism so as to override and disable the automatic stop mechanism when the control member is actuated.

A further object is to provide such a new and improved mechanism in which the portion of the automatic stop mechanism which is operable by upward movement of the corner separator is moved away from the corner separator by the overriding connection to the feed mechanism, sothat the automatic stop mechanism does notinterfere with the free movement of the corner separator during the normal operation of the feed mechanism.

It is a further object toprovide such an automatic stop mechanism in which the corner separator, upon upward movement thereof, engages a lever which causes a stop pawl to move into engagement with a stop ratchet wheel on the manually rotatable shaft for raising the feed table, and in which the operation of the control member which starts the feeding of the paper sheets is effective not only to move the stop pawl away from the ratchet wheel, but

also to move the lever out of the path of the corner separator.

Further objects and advantages of the present invention will appear from the following description, taken with the accompanying drawings, in which:

FIG. 1 is a diagrammatic elevational view of a duplicating machine which embodies the present invention.

FIG. 2 is a fragmentary diagrammatic elevational view showing components of the automatic stop mechanism, employed in the duplicator of FIG. 1, for arresting the manual raising movement of the feed table at the desired elevation, the components being shown in their initial positions, before the feed table has been raised manually.

FIG. 3 is a view similar to FIG. 2, but showing the components of the automatic stop mechanism in changed positions, after the upward movement of the feed table has been arrested.

FIG. 4 is a view similar to FIG. 2, but showing additional components whereby the automatic stop mechanism is linked to the feed control lever, so that actuation of the feed control lever overrides the stop mechanism.

FIG. 5 is a perspective view of a stop pawl employed in the automatic stop mechanism of FIGS. 2-4.

FIG. 6 is a perspective view of a sliding component shown in FIG. 4.

FIG. 7 is a fragmentary plan view of the stop mechanism, partly in section, along the broken line 7-7 in FIG. 3.

FIG. 8 is a fragmentary elevational view, with the removable feed table detached from the machine, taken generally as indicated by the line 8-8 in FIG. 3.

FIG. 9 is a diagrammatic elevation view showing components of the power opera-ted mechanism whereby the feed table is intermittently raised as the sheets are fed therefrom.

FIG. 10 is a fragmentary section taken generally along the line ll01ll in FIG. 9.

As already indicated, FIG. 1 illustrates a duplicating machine 20, which in this case is of the stencil type. However, it will be understood that the present invention is applicable to duplicating machines generally, and also to printing presses and other machines in which sheets of paper or other thin material are fed from a stack or pack. The illustrated duplicator Zll comprises a main cylinder or drum 22 which is adapted to receive the stencil or other printing member. The sheets of paper are adapted to be fed between the main cylinder 22 and an impression cylinder 24 which presses the sheets against the main cylinder so that each sheet will receive the imprint of the stencil or other printing member.

The duplicator 20 comprises a feed table 26 which is adapted to support a stack 28 of the paper sheets 30. A feed mechanism 32 is provided to feed the sheets 30 one at a time from the top of the stack 28. The illustrated feed mechanism 32 comprises one or more frictional feed rollers 34 which are adapted to engage the topmost sheet in the stack 28 and to propel the topmost sheet forwardly from the stack. To insure that only the topmost sheet will he slid off the top of the stack, the illustrated feed mechanism 32 employs either one or two corner separators 36. Various features of the illustrated corner separators are disclosed in the Tonkin Patent No. 2,912,241, and the Perzentka Patent No. 2,922,644. Each of the illustrated corner separators 36 comprises a vertical bar 38 which is positioned in front of one of the front corners of the stack. A flange or lip 40 extends rearwardly from the upper end of the vertical bar 38 and is adapted to be supported by the top of the paper stack 28. The flange 40 is normally triangular in shape and is adapted to extend diagonally across one of the front corners of the topmost sheet in the stack.

When the topmost sheet of paper is slid off the stack by the feed rollers 34, the front corners of the sheet buckle rearwardly and inwardly as they pass the corner separators 36. The buckling of the topmost sheet enables the corners to snap past the corner separators. This buckling action of the corner separators has the effect of positively separating the topmost sheet from the underlying sheets in the stack, so that only the topmost sheet will be fed off the stack.

The topmost sheet is fed into a chute or opening 42 between converging upper and lower guide plates 44 and 46 which guide the sheet into the nip between upper and lower forwarding rollers 48 and 50. The sheet is propelled forwardly by the rollers 48 and 50 into a gripping device 52 which is carried between a pair of endless conveyor chains 54. It will be seen that the chains 54 are strung around sprockets 56 and 60. The sprockets 56 may be driven in timed relation to the rotation of the main cylinder 22. A guide plate 62 is provided to direct the sheet into the gripping device 52. It will be seen that the gripping device 52 carries the sheet between the main and impression cylinders 22 and 24. A longitudinal notch or recess 64 is formed in the impression cylinder 24 to receive the gripping device 52 as it passes between the cylinders 22 and 24. The impression cylinder 24 is registered with the conveyor chains 54 so that the gripping device 52 will register with the notch 64. Various features of the registering mechanism are disclosed and claimed in the copending application of George I. Zahradnik and Fred S. Golden, Serial No. 370,028, filed May 5, 1964.

After the sheet has passed between the cylinders 22 and 24, it is released by the gripping device 52 and is stripped therefrom by strippers 66. The printed sheet then is directed into a receiving tray 68.

The feed table 26 is vertically movable and is adapted to be raised and lowered so that the stack 28 of paper may be raised to the desired level for efficient operation of the feed mechanism 32. In this case, the feed table 26 is detachably mounted on a vertically movable carriage 70. Vertical slots 72 and 74 are formed in the frame plates 76 (FIG. 7) of the machine to guide the carriage 70 for vertical movement. The carriage 70 is fitted with members or blocks 78 (FIG. 1) and 80 which are slidably received in the slots 72 and 74. The illustrated carriage 70 comprises upper and lower cross-rods 82 and 84 on which the feed table 26 is detachably mounted. The feed table 26 may have a pair of side plates 86 which may be formed with slots 88 for receiving the upper cross-rod 82. Arms 90 project downwardly from the side plates 86 and are adapted to engage the lower cross-rod 84. It will be evident that the feed table 26 may readily be unhooked from the upper crossrod 82 and lifted clear of the machine.

Various means may be provided to raise and lower the feed table 26. As shown, the supporting carriage 70 is provided with vertical gear racks 92 which are engaged by pinions 94 on an operating shaft 96. To raise the feed table 26, the shaft 96 is rotated clockwise, as seen in FIG. 1.

As in the case of many duplicators and machines of this type, the machine is provided with an automatic feed table raising mechanism 98 (FIG. 9) which is adapted to raise the feed table intermittently, during the operation of the machine, so that the top of the paper stack 28 will be maintained at a nearly constant elevation, as the paper sheets are fed from the top of the stack. Automatic table raising mechanisms of this general type are well known to those skilled in the art, so that it will not be necessary to enter into a full description of the automatic mechanism 98 employed in the present machine. However, certain of the details of the automatic table raising mechanism 98 are of interest in connection with the automatic stop mechanism to which the present invention relates. Thus, it will be of interest to note that the table raising mechanism 98 comprises a ratchet wheel 100 which is mounted on the shaft 96. Two pawls 102 and 104 are normally in engagement with the ratchet wheel 100. The pawl 102 is an actuating pawl which is operated intermittently to raise the feed table 26. The pawl 104 is a non-retrograde pawl which prevents retrograde movement of the ratchet wheel 100 and thereby maintains the table 26 in its raised position. It will be understood that the ratchet wheel 100 is rotated clockwise by the actuating pawl 202 so as to raise the feed table 26. Retrograde or counterclockwise rotation of the ratchet wheel 100 is normally prevented by the non-retrograde pawl 104. It will be seen that the non-retrograde pawl 104 is swingable about a stationary pivot 106. Both pawls 102 and 104 are normally biased against the ratchet wheel 100 by a tension spring 108 which is stretched between lever arms 110 and 112 on the respective pawls 102 and 104.

The actuating pawl 102 is swingably mounted on a pivot 114 which is carried by an actuating lever 116. In this case, the actuating lever 116 is mounted on the shaft 96 for free swinging movement relative thereto. The actuating lever 116 is biased in a counterclockwise direction by a tension spring 118 which is stretched between the fixed pivot 106 and one arm 120 of the lever 116.

When the top of the paper stack 28 drops below a predetermined level, the actuating lever 116 is caused to swing clockwise so as to advance the ratchet wheel 100 through one step. The power for operating the lever 116 is derived from a cam follower lever 122 which is continuously oscillated during the normal operation of the machine. A switch link 124 is swingably mounted on a pivot 126 carried by the actuating lever 116 and is aldapted to form a disengageable connection between the cam follower lever 122 and the actuating lever 116. Thus, the switch link 124 is formed with a hook 128 which normally is out of the path of the cam follower lever .122 but is movable downwardly into the path of an ear or flange 130 on the lever 122. A spring 132 is provided to bias the switch link 124 upwardly. It Will be seen that the spring 132 is connected between the pivot 114 and a tab or ear 134 on the switch link 124. The switch link 124 may be operated by a suitable mechanism responsive to the depletion of the paper on the feed table 26. Various mechanisms of this kind will be well known to those skilled in the art.

Provision is made for lowering the feed table 26 by moving both of the pawls 102 and 104 away from the ratchet wheel 100 so as to release the ratchet wheel for counterclockwise movement. The weight of the feed table then causes it to drop downwardly as far as it will go. As shown in FIG. 9, the pawls 102 and 104 are adapted to be moved away from the ratchet wheel 100 by a slidable plate or member 136 which is formed with a slot 138 to receive the hub 140 of the ratchet wheel 100. When the plate 136 is slid to the right, it engages the pawls 102 and 104 and moves them away from the ratchet wheel 100. A spring 142 is provided to bias the plate 136 to the left. It will be seen that the spring 142 is stretched between a bracket 144 and an ear 146 on the plate 136. In this case, the plate 136 is operated by a manually operable push button 148. A slidable pin or shaft 150 extends rearwardly from the push button and engages one arm of a bell crank lever 152. The other arm of the lever 152 engages the plate 136 and is adapted to move the plate to the right. The shaft 150 extends through a slot 154 in the plate 136.

As will be seen from FIG. 7, the table raising shaft 96 is provided with a knob or hand wheel which may be turned in a clockwise direction to raise the feed table 26. A chain 162 is wrapped around a hub 164 on the shaft 96 adjacent the hand wheel 160 and is connected to a spring, not shown, to partially counterbalance the weight of the feed table 26, so that the effort required to raise the feed table will be reduced. When the knob 160 is turned to raise the table 26 the non-retrograde pawl 184 snaps over the teeth of the ratchet wheel 100 and maintains the table 26 in its raised position.

When the feed table 26 is reloaded with a new stack of paper, it is a normal practice to stop the machine and lower the feed table as far as it will go by pressing the release button 148 so as to disengage the pawls 102 and 104 from the ratchet wheel 180. The stack of paper is then placed on the feed table 26. The feed table 26 is then raised manually to an elevation such that the feed mechanism 32 and the corner separators 36 will be fully operative in the normal manner. The illustrated duplicator 21) is provided with an anutomatic stop mechanism 166, whereby the manual raising movement of the feez'd table 26 is automatically arrested when the top of the paper stack 28 has been raised to the correct level. In this case, the level of the top of the stack is determined and controlled by the corner separators 36, which serve as feelers adapted to be engaged and raised by the top of the stack when it is moved upwardly to the desired elevation. As already indicated, the lip or flange 40 of each corner separator 36 is supported by the top of the paper stack during normal operation of the feed mechanism 32. Thus, the stack of paper should be raised until the top of the stack engages and supports the lips 46, before the feed mechanism 32 is started. The automatic stop mechanism 166 is operative to arrest the manual raising movement of the feed table 26 when the top of the stack 28 engages and starts to raise the lips 46 of the corner separators 36. Thus, the manual raising of the feed table is greatly simplified in that the operator merely turns the table raising knob 1611 clockwise as far as it will go.

In the illustrated construction, each corner separator 36 is fitted with a supporting pin 168 which is riveted or otherwise secured to the vertical bar portion 38. The pin projects rearwardly 'from the bar 38 and is loosely received in a horizontal slot 170 formed in a vertical supporting plate 172 (FIG. 8). A small plate or finger 174 is secured to and projects downwardly from the rear end of the supporting pin 168 to retain the pin in the slot 174 The retaining plate 174 extends downwardly behind the supporting plate 172. Initially, the pin 168 forms the sole support for the corner separator 36. However, dur ing the normal operation of the feed mechanism 32, the lip 40 of the corner separator 36 is supported by the paper stack 28, and the separator is raised above its initial position so that the pin 168 floats freely between the upper and lower edges 176 and 17 8 of the slot 178. The height or width of the slot 170 is considerably greater than the diameter of the pin 168 so that the corner separator 36 may move vertically through a limited range as the level of the paper changes due to the [feeding of the sheets and the action of the automatic feed table raising mechanism.

The automatic stop mechanism 166 comprises a second ratchet wheel 180 which is secured to the table raising shaft 96. As shown to best advantage in FIGS. 2 and 3, the ratchet wheel 180 has a plurality of ratchet teeth 182 which slope in a direction opposite to the slope of the teeth 184 on the ratchet wheel 180 for the automatic table raising mechanism. The second ratchet wheel'l8tl is adapted to be engaged by a stop pawl 186 which is effective to arrest clockwise movement of the ratchet wheel 186 and thereby prevent further raising movement of the tffifid table 26. The illustrated pawl is swingable about a fixed pivot 188. The automatic stop mechanism 166 is arranged so that the pawl 186 is swung against the ratchet wheel 188 when the corner separators 36 are raised by the paper stack 28.

In the illustrated mechanism 166, this is achieved by providing a member 196 which is adapted to be engaged and moved upwardly by the supporting pins 168 of the corner separators 36. As shown, the member 190 takes the form of a plate which is secured to and swingable with a horizontal shaft 192. The plate 190 is horizontally elongated so that it will be operated by the upward movement of the corner separators 36, regardless of the position to which the corner separators may be adjusted along the 'guide slot 178 in the supporting plate l'72. A lever 19 4 is mounted on the shaft 192 and is adapted to operate the stop pawl 1 86. In this case, the lever 194 is connected to the stop pawl by a tension spring 196 which is stretched between ears 1 98 and 20th on the pawl 186 and the lever 11 4. An adjustable thrust connection or stop 282 is also provided between the pawl 186 and the lever 194. As shown, the thrust connection 282 comprises an adjusting screw 204 which is mounted on the ear 198 and is engageable with an ear or flange 286 on the lever 194. The force of the spring 196 normally maintains the ear 286 in engagement with the adjusting screw 2114. In addition, the spring 196 biases the lever 1'94 counterclockwise to a position in which the plate 198 projects into the upward paths of the supporting pins 168 on the corner separators 36. The lever 64 has an arm 207 which is engageable with a stop pin 289 to limit counterclockwise movement of the lever. The engagement of the stop screw 264 with the ear 206 normally holds the stop pawl 186 away from the ratchet wheel 1-81). The spring 1% is connected between the lever 194 and the pawl 186 at positions such as to provide a multiplication of leverage so that a slight movement of the plate causes a great movement of the pawl 186.

When the corner separators 36 are moved upwardly by the paper stack 28, the pins 168 engage the plate 1% and swing it clockwise. The resulting movement of the lever 194 causes the pawl 186 to move against the ratchet wheel 188. The connecting spring 196 causes the pawl 186 to follow the movement of the lever 194.

The automatic stop mechanism 166 is arranged so as to obviate any possibility of interference with corner separators 36 or the automatic table raising mechanism 98 during the normal operation of the machine. Means are provided to override the action of the automatic stop mechanism when the feed mechanism 32 is in normal operation. In this way, the corner separators 36 will be free to move vertically, and the feed table 26 will be entirely free to be raised by the automatic table raising mechanism.

Thus, FIG. 4 illustrates an overriding mechanism 218 which is adapted to be operated by a control lever 212, forming part of the feed mechanism 32. Feed mechanisms having such control levers are well known to those skilled in the art, so that it will not be necessary to enter into a detailed description of the manner in which the lever 212 controls the feed mechanism. It will suftice to note that the lever 212 is adapted to start and stop the operation of the feed mechanism '32. The lever 212 is movable between the positions shown in full and broken lines in FIG. 4. In the full line position, the feed mechanism is stopped. The operation of the feed mechanism is started by shifting the lever 2 12 clockwise, to the broken line position.

The overriding mechanism :210 comprises an elongated link 214 which is .connected to the control lever 212 by means of a pivot 216. The lower end of the link 214 is provided with a slot 218 which is slidably received over the pin 209 which guides the link for generally vertical movement. The link 214 is adapted to operate a slider 222 which in turn is engageable with the lever 194 and the stop pawl 186. FIG. 6 shows the slider 222 in perspective. The slider 222 is also shown in FIG. 4 in its assembled relation to the other components of the mechanism.

It will be seen that the slider 222 is formed with upper and lower guide slots .224 and 226. The upper guide slot 224 is received over the guide pin 209, while the lower guide slot 226 is received over the pivot 188 for the stop pawl 186. The slider 222 is formed with an outwardly projecting ear or flange 228 which is adapted to he engaged by upper and lower shoulders or edges 23'].

'5 and 232 on the lower end of the link 214. When the link 214 is moved upwardly by the control lever 212, the shoulder 232 engages the car 228 and raises the slider 222. When the control lever 212 is moved downwardly, the upper shoulder 231 engages the car 228 and moves the slider 2Z2 downwardly.

The upward movement of the slider 222 is effective to swing the stop pawl 1.86 away from the ratchet wheel 1 80. This is brought about by another tab 234 on the slider 222. The "tab 234 is engageable with a pin 236 which is mounted on the stop pawl 186. When the slider 222 is moved upwardly, the tab 234 pushes the pin 236 upwardly and thereby raises the pawl 1845.

The upward movement of the slider 222 is also effective to swing the lever 194 in a clockwise direction so as to move the plate 190 out of the paths of the supporting pins 168 on the corner separators 36. This is brought about by an car 237 on the slider 222. The ear 237 is adapted to engage a laterally projecting arm or finger 238 on the lever 194. Thus, the ear 237 pushes the arm 23? upwardly when the slider 222 is moved upwardly. In this way, the plate 190 is swung clockwise so as to be completely clear of the corner separators 36.

It will be noted that the upward movement of the slider 222 causes clockwise movement of both the stop pawl 186 and the lever 194. Accordingly, the stop screw 2% and the ear 206 move apart, while the spring 196 is stretched. Thus, the resilient connection afforded by the spring 196 accommodates the overriding action of the link 214 and the slider 2 22.

While the operation of the machine has been described, it may be helpful to offer a brief summary of the operation. on the feed table 26, the feed table is dropped to its lowermost position by pushing the button 148, which causes movement of the release member 166 to the right (FIG. 9). The member 136 pushes the pawls 102 and 104 away from the ratchet wheel 1%, whereupon the weight of the feed table causes the feed table to drop to its lowermost position. The new stack of paper is then placed on the feed table 26.

Next, the feed table is raised manually by turning the knob 160 clockwise. The automatic stop mechanism 166 arrests the upward movement of the feed table 26 when the paper stack 28 engages and raises the corner separators 3'6. Thus, the operation of manually raising the feed table is greatly simplified inasmuch as the operator merely turns the knob 16% as far as it will go.

When the paper stack 28 engages the lips 44) and causes the corner separators 36 to move upwardly, the supporting pins 168 of the corner separators push the plate 190 upwardly and in a clockwise direction, so that the shaft 192 and the lever 194- are rotated clockwise. The spring 196 pulls the stop pawl 1 .86 in a counterclockwise direction so that the pawl is'moved into engagement with the second ratchet wheel 180. The engagement of the pawl 186 with the reversely sloping teeth 182 of the ratchet Wheel 18% arrests the clockwise rotation of the shaft 96 and prevents further raising movement of the feed table 26.

The operator then starts the operation of the feed mechanism 32 by raising the control lever 212. This in turn raises the link 2M and the slider 222. The tab 234 on the slider Z22 engages the pin 236 and swings the stop pawl 186 in a clockwise direction, out of engagement with the ratchet wheel 180. The ear 237 on the slider 222 engages the finger 238 and swings the lever 194 in a clockwise direction so as to move the plate 190 completely away from the corner separators 36. Thus, the plate 190 is prevented from interfering with the vertical movement of the corner separators 36, so that the corner separators are freely supported by the top of the paper stack and are enabled to function in a completely normal manner. Moreover, the overriding action of the link 214 and the slider 222 prevents the stop pawl 186 from interfering When it is desired to place a new stack of paper with the operation of the automatic feed table raising mechanism 98, so that the mechanism 98 is free to raise the feed table, step by step, as the stack of sheets is de pleted by the action of the feed mechanism.

It will be evident that the automatic stop mechanism greatly simplifies the operation of manually raising the feed table. At the same time, the automatic stop mechanism insures that the feed table is raised to the correct level.

Various other modifications, alternative constructions and equavilents may be employed without departing from the true spirit and scope of the invention, as exemplified in the foregoing description and defined in the following claims.

I claim:

ll, In a duplicating machine, the combination comprising a feed table for holding a stack of paper sheets, a feed mechanism for feeding the sheets one at a time from the top of the stack, said mechanism including a manually operable control member movable from an inactive position to an active position for starting the operation of said feed mechanism, means supporting said feed table for raising and lowering movement, a generally vertical rack connected to said feed table, a rotatable pinion meshing with said rack, a rotatable shaft connected to said pinion, a manually operable knob on said shaft for raising said feed table, an automatic feed table raising mechanism including a first ratchet wheel mounted on said shaft, a power operated pawl engaging said ratchet wheel for intermittently advancing said ratchet wheel to raise the feed table, a non-retrograde pawl engaging said ratchet wheel to prevent retrograde movement of said wheel, an automatic stop mechanism including a second ratchet wheel mounted on said shaft, said first ratchet wheel having teeth sloping in one direction while said second ratchet wheel has teeth sloping in the opposite direction, at least one corner separator mounted adjacent said feed table for vertical movement, said separator having a flange engageable with and supported by the top of the stack of paper sheets, a stop pawl movable into engagement with said second ratchet wheel for arresting the manual rotation of said shaft and thereby stopping the manual raising movement of said feed table, means biasing said stop pawl away from said second ratchet wheel, means including a lever operable by upward movement of said corner separator for moving said stop pawl into engagement with said second ratchet wheel, the manual raising of said feed table thereby being stopped when the top of the paper stack raises said corner separator, and means operable by said control member of said feed mechanism for moving said stop pawl away from said second ratchet wheel, while also moving said lever away from said corner separator when said control member is moved to its active position to start the operation of said feed mechanism.

2. In a mechanism for handling sheets, the combination comprising a table for holding a stack of the sheets, means supporting said table for raising and lowering movement, a manually rotatable shaft having an operative connection to said table for raising said table, a stop ratchet wheel on said shaft, a stop pawl movable against said ratchet wheel for arresting the raising movement thereof, an element engageable by and movable upwardly with the top of the stack on said table, and means operable by upward movement of said element for moving said stop pawl into engagement with said ratchet wheel.

3. In a mechanism for handling sheets, the combination comprising a table for holding a stack of the sheets, means supporting said table for raising and lowering movement, a manually rotatable shaft having an operative connection to said table for raising said table, a stop ratchet wheel on said shaft, a stop pawl movable against said ratchet wheel for arresting the raising movement of said table, and means operable by upward movement of the stack to a predetermined level for moving said stop pawl into engagement with said ratchet wheel.

4. In a mechanism for handling sheets, the combination comprising a table for holding a stack of sheets, a feed mechanism for feeding sheets from said stack, a manu ally rotatable shaft having an operative connection to said table for raising said table, a stop ratchet wheel on said shaft, a stop pawl movable against said ratchet wheel for arresting the raising movement of said table, means operable by upward movement of said stack to a predetermined level for moving said stop pawl into engagement with said stop ratchet wheel, and means overable by starting of said feed mechanism for overriding said last-mentioned means and moving said stop pawl away from said ratchet wheel.

5. In a mechanism for handling sheets, the combination comprising a feed table for holding a stack of sheets, at least one corner separator mounted adjacent said table and having a lip engagea-ble with and supported by the top of the stack, a feed mechanism for feeding sheets from said stack and past said corner separator, said feed mechanism including a movable control member for starting the operation of said feed mechanism, a rotatable shaft having an operative connection to said feed table for raising said feed table, a stop ratchet wheel mounted on said shaft and rotatable therewith, a stop pawl movable against said ratchet wheel for arresting the upward movement of said table, an element engageable by said corner separator and operable by upward movement thereof for moving said stop pawl against said ratchet wheel to arrest the upward movement of said table, and overriding means operable by said control member of said feed mechanism for moving said stop pawl away from said ratchet wheel while also moving said element away from said corner separator.

6. In a mechanism for handling sheets, the combination comprising a feed table for holding a stack of the sheets, at least one corner separator mounted adjacent said table and having a lip engagea-ble with and adapted to be supported by the top of the stack, a feed mechanism for feeding sheets from said stack and past said corner separator, said feed mechanism including a movable control member for starting the operation of said feed mechanism, a rotatable shaft having an operative connection to said feed table for raising said table, a stop ratchet wheel mounted on said shaft and rotatable therewith, a stop pawl movable against said ratchet wheel for arresting the upward movement of said table, an element engageable by said corner separator and operable by upward movement thereof, spring means for moving said top pawl against said ratchet wheel in response to operation of said element so as to arrest the upward movement of said table, and overriding means operable by said control member of said feed mechanism for moving said stop pawl away from said ratchet wheel while also moving said element away from said corner separator, said spring means accommodating the :action of said overriding means.

7. In a mechanism for handling sheets, the combination comprising a feed table for holding a stack of sheets, at least one corner separator mounted adjacent said table and having a lip engageable with and adapted to be supported by the top of the stack, a feed mechanism for feeding sheets from said stack and past said corner separator, said feed mechanism including a movable control member for starting the operation of said feed mechanism, a rotatable shaft having an operative connection to said feed table for raising said feed table, a stop ratchet wheel mounted on said shaft and rotatable therewith, a stop pawl engageable with said ratchet wheel, a swingable plate engageable by said corner separator and operable by upward movement thereof for moving said stop pawl against said ratchet wheel to arrest the upward movement of said table, and overriding means operable by said control member of said feed mechanism for moving said stop pawl away from said ratchet wheel while also moving said swingable plate away from said corner separator to obviate interference with the free movement of said table and said corner separator during operation of said feed mechanism.

8. In a mechanism for handling sheets, the combination comprising a feed table for holding a stack of sheets, at least one corner separator mounted adjacent said table and having a lip adapted to be supported by the top of the stack, a feed mechanism for feeding sheets from said stack and past said corner separator, said feed mechanism including a movable control member for starting the operation of said feed mechanism, a rotatable shaft having an operative connection to said feed table for raising said feed table, a stop ratchet wheel mounted on said shaft and rotatable therewith, a stop pawl engageable with said ratchet wheel, a lever including a swingable plate engageable by said corner separator and operable by upward movement thereof, spring means connected between said lever and said pawl for moving said pawl against said ratchet wheel to arrest the upward movement of said table in response to upward movement of said corner separator, and overriding means operable by said control member for moving said stop pawl away from said ratchet wheel while also moving said swingable plate away from said corner separator to obviate any interference with the free movement of said table and said corner separator during operation of said feed mechanism, said spring means accommodating the action of said overriding means.

9. In a sheet feeding mechanism, the combination comprising a table for holding a stack of sheets, a feed mechanism for feeding the topmost sheet from the stack, said feed mechanism including control means for starting the operation thereof, manually operable means having an operative connection to said table for raising said table, a first stop member op-eratively connected to said table and movable concurrently therewith, a second stop member movable against said first stop member for arresting the raising movement of said table, an element engageable by and movable upwardly with the top of the stack on said table, means operable by upward movement of said element for moving said second stop member into engagement with said first stop member to stop the raising movement of said table, and means operable by said control means for overriding said last-mentioned means so as to move said second stop member away from said first stop member when the operation of said feed mechanism is started.

10. In a sheet feeding mechanism, the combination comprising a table for holding a stack of sheets, at least one corner separator mounted adjacent said table and having a lip engageable with and adapted to be supported by the top of the stack, a feed mechanism for feeding sheets from the stack and past said corner separator, said feed mechanism including control means for starting the operation thereof, manually operable means having an operative connection to said table for raising said table, a first stop member operatively connected to said table and movable concurrently therewith, a second stop member movable against said first stop member for arresting the raising movement of said table, means operable by upward movement of said corner separator for moving said second stop member against said first stop member to stop the raising movement of said table, and overriding means operable by said control means for moving said second stop member away from said first stop member when the operation of said feed mechanism is started.

11. In a mechanism for handling sheets, the com-bination comprising a table for holding a stack of the sheets, means supporting said table for raising and lowering movement, manually operable means having an operative connection to said table for raising said table, a first stop member connected to said table and movable concurrently therewith, said first stop member having a series of teeth thereon, a second stop member movable against said teeth of said first stop member for stopping the raising move- 1 1 ment of said table, an element engageable by and movable upwardly with the top of the stack on said table, and means operable by upward movement of said element for moving said second stop member into engagement with said first stop member to stop the raising movement of said table.

12. In a sheet feeding mechanism, the combintion comprising a table for holding -a stack of sheets, at least one corner separator mounted adjacent said table and having a lip engageable with and adapted to be supported by the top of the stack, a feed mechanism for feeding sheets from the stack and past said corner separator, said feed mechanism including control means for starting the operation thereof, manually operable means having an operative connection to said table for raising said table, a first stop member connected to said table and movable concurrently therewith, said first stop member having a series of teeth thereon, a second stop member movable against said teeth of said first stop member for stopping the raising movement of said table, means operable by upward movement of said corner separator for moving said second stop member against said first stop member to stop the raising movement of said table, and overriding means operable by said control means for moving said second stop member away from said first stop member when the operation of said feed mechanism is started.

13. In a sheet handling mechanism, the combination comprising a table for holding a stack of sheets, means supporting said table for raising and lowering movement, a manually rotatable shaft having an operative connection to said table for raising said table, a toothed wheel on said shaft, a stop pawl movable against said toothed wheel for arresting the raising movement of said table, an element engageable by and movable upwardly with the top of the stack on said table, and means operable by upward movement of said element for moving said stop pawl into engagement with said toothed wheel to stop the raising movement of said table.

14. In a sheet feeding mechanism, the combination comprising a table for holding a stack of sheets, at least one corner separator mounted adjacent said table and having a lip engageable with and adapted to be supported by the top of the stack, a feed mechanism for feeding sheets from the stack and past said corner separator, said feed mechanism including control means for starting the operation thereof, a manually rotatable shaft having an operative connection to said table for raising said table, a toothed wheel secured to said shaft, a stop pawl movable against said toothed wheel for arresting the raising movement of said table, means operable by upward movement of said corner separator for moving said stop pawl into engagement with said toothed wheel to stop the raising movement of said table, and overriding means operable by said control means of said feed mechanism for moving said stop pawl away from said toothed wheel when the operation of said feed mechanism is started.

15. In a sheet feeding mechanism, the combination comprising a table for holding a stack of sheets, at least one corner separator mounted adjacent said table and having a lip engageable with and adapted to be supported by the top of the stack, a feed mechanism for feeding sheets from the stack and past said corner separator, manually operable means having an operative connection to said table for raising said table, a first stop member operatively connected to said table and movable concurrently therewith, a second stop member movable against said first stop member for arresting the raising movement of said table, and means operable by predetermined upward movement of said corner separator for moving said second stop member against said first stop member to stop the raising movement of said table with the top of the stack at an elevation such as to support said lip of said corner separator.

References Cited by the Examiner UNITED STATES PATENTS 415,877 11/1889 Mont Ross 271 62 1,072,937 9/1913 Freeman 27l--62 2,922,644 l/l960' Perzentka 271-39 M. HENSON WOOD, JR., Primary Examiner.

J. N. ERLICH, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,273,884 September 20, 1966 George J, Zahradnik that error appears in the above numbered pat- It is hereby certified d that the said Letters Patent should read as ent requiring correction an corrected below.

Column 4, line 9, for "202" read 102 column 6, line 19, for "94" read 194 column 9, line 10, for "overable" read operable Signed and sealed this 22nd day of August 1967.,

(SEAL) ttest:

ERNEST W. SW'IDEB.

Attesting Officer EDWARD J. BRENNER Commissioner of Patents 

2. IN A MECHANISM FOR HANDLING SHEETS, THE COMBINATION COMPRISING A TABLE FOR HOLDING A STACK OF THE SHEETS, MEANS SUPPORTING SAID TABLE FOR RAISING AND LOWERING MOVEMENT, A MANUALLY ROTATABLE SHAFT HAVING AN OPERATIVE CONNECTION TO SAID TABLE FOR RAISING SAID TABLE, A STOP RACHET WHEEL ON SAID SHAFT, A STOP PAWL MOVABLE AGAINST SAID RATCHET WHEEL FOR ARRESTING THE RAISING MOVEMENT THEREOF, AN ELEMENT ENGAGEABLE BY AND MOVABLE UPWARDLY WITH THE TOP OF THE STACK ON SAID TABLE, AND MEANS OPERABLE BY UPWARD MOVEMENT OF SAID ELEMENT FOR MOVING SAID STOP PAWL INTO ENGAGEMENT WITH SAID RATCHET WHEEL. 